The present invention relates to an insulated panel arrangement for insulated panels such as those used in walk-in coolers.
Walk-in coolers and environmental test chambers are typically constructed of individual, insulated panels which are then latched together with hooks on one panel which engage pins on a second panel. The hooks are mounted on a cam arrangement so they can be rotated to pull the panels tightly together. The panels typically are fabricated from an expanded polyurethane foam insulation which is blown in between walls of relatively thin metal skins (typically 22 gauge steel or stainless steel). The panel ends are designed to match up in a tongue and groove configuration with the ends of the metal skins abutting each other.
The latch mechanisms are encased in the foam insulation. If the latch mechanisms shift relative to their respective panels, the fit between the panels may become loose, which is undesirable, as it allows air to leak through the gaps that are created between the panels and may affect the structural strength of the enclosure.
Prior art attempts to prevent shifting of the latch mechanisms relative to their respective panels have included the addition of “wings”, as shown in U.S. Pat. No. 6,299,224 “Finkelstein”, which is hereby incorporated herein by reference. The “wings” provide a large bearing surface for the latch mechanism to bear against the foam insulation to try to reduce the amount of shifting of the latch. However, in some instances, particularly when the foam insulation is subjected to very high temperatures or when it is exposed to high relative humidity, the foam insulation begins to break down, and the latches still become loose.
In very high temperature applications, such as in oven chambers, mineral wool insulation is used in the core space instead of foam insulation. Mineral wool insulation is not capable of bearing any weight, so it cannot be used as a structural member. Since the temperature differential in these panels is even greater than in the foam insulated panels, it is especially desirable to keep the heat transfer between the inner skin of the panel (inside the oven chamber) and the outer skin of the panel to a minimum.